Syria airstrikes: The critical message Trump sent to North Korea, China and Russia

President Trump's limited, proportional missile strike on a single Syrian air base had a clear purpose: Punish Syrian President Bashar al-Assad for having launched a chemical weapons attack that killed over 85 of his citizens and deter him (and others) from engaging in similar WMD-related war crimes.

The strike was not aimed at toppling Mr. Assad or ousting his minority Alawite regime, at least, not yet. Removing Mr. Assad would undermine what Mr. Trump has long called his key foreign policy objective — defeating the Islamic State in Iraq and Syria and the other most dangerous Islamists who have destabilized much of the Middle East.

But the launching of some 59 sea-based Tomahawk cruise missiles against the Syrian Air Force's base of Shayrat sends a strong message not only to Syria but to several other states and groups with a stake in the outcome of that country's brutal civil war.

To North Korea, the strike is a warning that Mr. Trump is willing to match action with his tough tweets warning that the U.S. will not permit Pyongyang to threaten American security by marrying its small nuclear arsenal with intercontinental ballistic missiles capable of reaching our shores. North Korea is also believed to possess chemical weapons which it could reign down on Seoul and American forces stationed near the South Korean capital in the event of conflict.

To China, it shows that Mr. Trump is prepared to make good on his pledge to take unilateral action against North Korea if Beijing is unwilling to pressure its mercurial neighbor into suspending, if not dismantling its own nuclear program.

And perhaps most important, the strike shows Russia that President Trump's unlikely bromance with Russia's autocratic ruler Vladimir Putin has its limits, and that Mr. Trump is likely to insist that Mr. Putin stop making excuses for his brutal client and contain Mr. Assad's most outrageous conduct. Military action which throws Moscow off-balance could not come at a better time for Mr. Trump, whose administration is beset by multiple investigations into whether his campaign officials colluded with Russia in interfering in America's presidential election and whether such collusion helped elect Mr. Trump over his Democratic rival, Hillary Clinton.

Hours after the strike, Russia's senior spokesman Dmitry Peskov blasted the strike as a "violation of international law" and demanded an emergency meeting of the United Nations Security Council. He continued to deny that Syrian government forces possessed chemical weapons. Mr. Putin called the strike an "act of aggression against a sovereign nation."

But neither immediately cancelled U.S. Secretary of State Rex Tillerson's planned visit to Moscow next week, so the extent of Russian fury is still hard to gauge. Perhaps Mr. Putin was somewhat mollified by the Trump administration's decision to give Moscow advance warning of the strike through "deconfliction" or military channels. America's Tomahawk sea-launched cruise missiles apparently avoided targeting buildings on the airbase associated with Russian personnel and equipment.

Unlike President Reagan's 1986 bombing raid on Libya which was aimed at killing then President Muammar el-Qaddafi, Mr. Trump's strike was not aimed at taking out Syria's leadership, nor even its military's command-and-control structure. It was was directed at the one air base where U.S. intelligence believes deadly sarin gas was loaded into Syrian aircraft for Tuesday's deadly raid. Mr. Assad continues to live to fight another day, but if he heeds Donald Trump's dramatic warning, not with chemical weapons.

Mr. Trump's broader strategic objectives in Syria are still unclear. His administration, slow to appoint the assistant secretaries and other senior officials who make and oversee policy, is still a work in progress.

Mr. Trump himself and several of his senior officials have made conflicting statements about what they hope to achieve. While candidate Trump seemed to endorse the creation of "safe zones" in Syria to protect civilians fleeing the bloody conflict, President Trump has not recently spoken of such havens, which would probably require the deployment of more American soldiers to protect.

Until recently, Mr. Trump also seemed determined not to involve America more deeply in the civil war, even diplomatically. But after Thursday night's strike, he appeared to recast America's interest in the Syrian conflict, saying that in addition to Assad's chemical weapons, the region's instability was "threatening the United States and its allies." That seemed to open the possibility that he intends to pursue enhanced diplomacy to resolve the seven-year war which has killed an estimated 500,000 people, displaced millions more, and destabilized Europe through a flood of refugees.

Thursday's strike tells us only that developing and using WMD remains for Mr. Trump, as for previous presidents, a "red line" that nations dare not cross without potential consequences. But that, as Mr. Trump would say, is yuge.

Judith Miller, a Fox News contributor, is an award-winning author, and an adjunct fellow at the Manhattan Institute. Her latest book, "The Story: A Reporter's Journey" (Simon & Schuster, April 7, 2015). Charles Duelfer was deputy chairman of the U.N weapons inspection agency from 1993 to 2000 and led the Iraq Survey Group, the CIA-led team charged with hunting for WMD in Iraq.